Sofa



FIG. 1 is a perspective view of a sofa from the front and left side showing my new design. The broken lines immediately adjacent the shaded areas represent the bounds of the claimed design; the broken lines form no part of the claimed design;

FIG. 2 is a side elevational view of the right side thereof;

FIG. 3 is a rear elevational view thereof; and,

FIG. 4 is a top plan view thereof. 

The ornamental design for a sofa, as shown and described. 